The present invention relates to a paper feeding apparatus used in an apparatus such as a manuscript moving type image scanner, and more particularly to a paper feeding apparatus which can stably feed a manuscript paper even if the paper is thick.
Conventionally, there has been widely used an image scanner in which a manuscript paper is fed and an image thereon is read and computerized. In this image scanner, the manuscript papers are placed on a hopper and fed one by one to a paper conveying passage by means of a paper feeding roller, and then the image on the paper is read by an image reader provided on the paper conveying passage.
FIG. 3 is a schematic view of the conveying structure for a manuscript paper in a conventional image scanner, in which manuscript papers P are placed on a hopper 51 and a paper feeding roller 52 is disposed above the hopper 51 so as to contact with the uppermost manuscript paper P. On the downstream side of the paper feeding roller 52, there are disposed a separating roller 53 for preventing overlapped feeding of the manuscript papers P, and a retard roller 54 with a torque limiter therein. Further, on the downstream side of those, a plurality of pairs of conveying rollers 55a and 55b are disposed for nipping and conveying the manuscript paper P. In the middle of a conveying passage provided with the conveying rollers 55a and 55b, image reader 56 and 57 are disposed for optically reading a manuscript image on the manuscript paper P.
In the case of the paper feeding structure shown in FIG. 3, the manuscript paper P on the hopper 51 and the conveying passage are arranged substantially on a straight line, and the conveying passage including the conveying rollers 55a and 55b is horizontally arranged, so that the length of the conveying passage in the right and left direction (horizontal direction) in the drawing is long. Thus, the total length of the apparatus also becomes long, and the miniaturization of the apparatus is limited.
Accordingly, by inclining the conveying passage so that the left end side thereof tends upward, the plane length of the conveying passage becomes short, so that the apparatus is miniaturized, and besides, it is possible to install equipment such as a power source in the space under the conveying passage, so that the design flexibility is improved.
In the case that the conveying passage is inclined, however, a bending portion is formed in the paper feeding passage between the paper feeding roller 52 on the manuscript paper P placed on the hopper 51, and the separating roller 53 and retard roller 54 provided on the downstream side of the paper feeding roller 52. In this case, although thin paper can pass thorough the bending portion without trouble since it follows the bend, thick paper may not pass along the bend, that is, the paper may not be fed. Accordingly, in an image scanner for reading a manuscript image on various kinds of manuscript papers, it is impossible to read an image on the thick paper if the conveying passage is inclined for the miniaturization of the apparatus.
Accordingly, it is an object of the present invention to provide a paper feeding apparatus which is miniaturized by inclining a conveying passage and can feed a manuscript paper quickly, even if the paper is thick.
According to the invention, there is provided a paper feeding apparatus comprising a hopper for holding a sheet thereon, a conveying passage connected with the hopper, and a feeding device for feeding the sheet from the hopper to the conveying passage, wherein the conveying passage is inclined in the height direction so that the hopper side thereof is downward.
Preferably, the hopper is inclined in the height direction so that the hopper is substantially aligned with the conveying passage. Alternately, the inclination angle of the hopper may be variable between the horizontal angle and an angle at which the hopper is substantially aligned with the conveying passage.
The apparatus may further comprise a first passage branching upward from the upper end of the conveying passage, a second passage extending straight from the upper end of the conveying passage at the same inclination angle, and a switching device provided at the branch point for switching the passages.
The hopper may hold a plurality of sheets thereon, and the feeding device may comprise a feeding roller pressed on the uppermost one of the sheets for feeding the sheet one by one from the hopper to the conveying passage.
According to the present invention, since the conveying passage is inclined, the plane length of the apparatus can be shortened. Further, since the inclination angle of the hopper can be varied in correspondence with that of the conveying passage so that the sheet conveying direction becomes straight, the apparatus can quickly feed the sheet even if the sheet is a thick manuscript.
A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.